A widely used practice of labeling web, such as photographic film and paper, during coating is to manually apply adhesive, magnetic labels to a non-coated edge of the web. Labeling is generally required during coating of photographic media so as to identify the location of the start and finish of a "good" coated part. Typically, a coating operator would use a white light flashlight to apply the labels on alternating sides of the media or web during the first pass in which part changes are made; subsequent passes then utilize a magnetic detection alarm system to make the coating operator aware of the imminent presence of a "good" coated part at the coating hopper. However, the present labeling technique has several shortcomings. On the one hand, experience has shown that labels applied in the manner discussed tend to fail because of failure of the adhesive material. As a result the ability to distinguish between coated parts is lost. Another shortcoming of the existing practice for labeling photographic media during coating is that since the labeling must be done in the dark because of the photosensitivity of the media, there exists the possibility of media fogging due to the white light flashlight.
An even more significant shortcoming of current practice for labeling media is that it is virtually impossible for an operator to manually position a label at the precise location along the media when the media is advancing through the coating process at very high speeds exceeding about 90 ft/min.
In more advanced coating equipment, the use of a so-called Advanced Fluid Delivery System (AFD) system has created additional concerns and/or intensified existing ones. AFD coatings are shorter in length resulting in a larger number of coatings, and a coating operator would need to stand at the coating station for prolonged periods to apply the labels to the web at a much greater frequency (every minute over several hours). This could lead to a repetitive motion injury, and at the very minimum will keep the coating operator from being able to focus on other tasks.
Moreover, AFD coatings are generally shorter and therefore can less afford the potential of fogging at the start and end of the "good" part that may come with the physical labeling method.
Therefore, a need persists for an apparatus that can automatically apply bar code indicia to photographic media traveling at high speeds that is reliable, easy to use, and precisely locates the desired labeling position on the media without operator intervention.